The election of Donald Trump as president of the United States—a man who has praised dictators, encouraged violence among supporters, threatened to jail his rival, and labeled the mainstream media as “the enemy”—has raised fears that the United Statesmay be heading toward authoritarianism. While predictions of a descent into fascism are overblown, the Trump presidency could push the United States into a mild form of what we call “competitive authoritarianism”—a system in which meaningful democratic institutions exist yet the government abuses state power to disadvantage its opponents.

But the challenges facing American democracy have been emerging for decades, long before Trump arrived on the scene. Since the 1980s, deepening polarization and the radicalization of the Republican Party have weakened the institutional foundations that have long safeguarded U.S. democracy—making a Trump presidency considerably more dangerous today than it would have been in previous decades.

There is little reason to expect Americans’ commitment to democracy to serve as a safeguard against democratic erosion.

Paradoxically, the polarizing dynamics that now threaten democracy are rooted in the United States’ belated democratization. It was only in the early 1970s—once the civil rights movement and the federal government managed to stamp out authoritarianism in southern states—that the country truly became democratic. Yet this process also helped divide Congress, realigning voters along racial lines and pushing the Republican Party further to the right. The resulting polarization both facilitated Trump’s rise and left democratic institutions more vulnerable to his autocratic behavior.

The safeguards of democracy may not come from the quarters one might expect. American society’s purported commitment to democracy is no guarantee against backsliding; nor are constitutional checks and balances, the bureaucracy, or the free press. Ultimately, it may be Trump’s ability to mobilize public support—limited if his administration performs poorly, but far greater in the event of a war or a major terrorist attack—that will determine American democracy’s fate.